Controlling an extractor fan.

Although I a complete newcomer to Arduino's etc. I am starting a project to set up a 240v extractor fan controlled by an Arduino. The Arduino would be used to monitor the humidity and when it passed a certain level turn the fan on, then maintain that until it dropped to a predetermined level.

I need some guidance firstly on the hardware needed.

1 Would the temp/humidity sensor supplied in the kit be suitable or would something more sophisticated be better?
2 I have several relays of the type supplied in the kits etc. would these be suitable they are rated 240v?
3 I don't believe these are latching relays does that mean the need to have constant input to keep the fan switched on?

Very basic questions but I am starting at the very beginning.

Regards
John K.
Consistency is the last resort of the unimaginative.

What kit have you bought? There are a lot of kits available and if you link to the one you actually have it will help.

To be able to know if a particular relay will work with your fan you need to know how much current the fan draws.

Would the temp/humidity sensor supplied in the kit be suitable

That would depend on the specific sensor and your definition of "suitable".

Non-latching mechanical relays do, indeed, require current to the coil to stay energized. A solid state relay will as well, but the current is much less.

Thanks for replies, the kit I am starting out with is as the attached photo. The fan may be a smaller type bathroom or a kitchen extractor fan, this can change as necessary. It is for shed/workshop ultimately.

Regards
John K.

You really need to settle on a fan and know its specifications (rated voltage, stall current) before we can know if a particular relay will work with it.
And, hopefully your kit has the components necessary to drive a relay. Most relays require more coil current than an Arduino output can safely provide. You will also need a fly back diode across the relay coil to protect the driver.
No pictures, yet.